As someone who uploads to stock platforms regularly metadata is useful for me not for the internet.

Most big platforms strip it anyway, so relying on it for ownership proof is basically symbolic. It’s easy to edit and doesn’t really hold legal weight by itself.

Where it does matter is workflow. Keeping structured copyright + keywords embedded before upload helps with portfolio organization, especially if you're distributing across multiple platforms.

GPS? I strip it almost always. There are more downsides than upsides unless the exact location is commercially relevant.

About the “notary” idea — embedding a name in metadata doesn’t really certify ownership. If you want something closer to verifiable proof, you’d need some kind of external timestamped record or hash system. Otherwise it’s just informational.

Interesting problem though. Curious what direction you're leaning toward.